Island



F: E. STRATTON FLUID PRESSURE ACTUATED GRINDING MACHINE Aug '11, 1931-. 7

Re. 18,149 5 $heetsSheet 1 Original FiledFeo. V17, 1926 I @0577? J LZKG/r QWZZ F. E. STRATTON FLUID PRESSURE ACTUATED GRINDING MACHINE Aug. 11, 1931.

5 Sheets-Sheet" 2 Original Filed Feb Mug N I 1 J4wg/ 6 F. E. STRATTON FLUID PRESSURE ACTUATED GRINDING MACHINE Aug. 11, 1931.. '1 Re. 18,149

5 Sheets-Sheet Original Filed Feb. 17, 1926 F. E. STRATTON A 11 193LFLUID PRESSURE ACTUATED GRINDING MACHINE A Original Filed Feb; 17- 1925 5 Sheets Sheet F. E. STRATTON FLUID PRESSURE .ACTUATED GRINDING MACHINE Aug 11, 1931. I Re. 1

5' Sheets- 8,149 Sheet Original Filed Feb. 17, 1926 m "mnuh.

fiveziar m QM%' Reissue! Aug. 11,1931

UNITED STATES BEST AVAILABLE Re. 18,149

(PATENT OFFICE FRANK B. S'IBATTQN, OF CRANSTON, QHODE ISLAND, LSSIGNOR TO DIAMOND MACHINE COMPANY, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND FI|U1D PBJESUBE ACTUA'IED enmnme monnm Original No. 1,725,488, dated August 20, 1929, Serial. No. 88,805, fled February I7, 1928. Application for reissue ill ed lay $1, 1930. Serial N0. 158,765.

' My invention relates to grinding machines,

Liquid operated grinders, particulariy of the where the work carriage is reclprocate y liquid-pressure give a finer fimsh than mechanically reciprocated grinders. In mechanically 0 rated grinders, which are usually driven y gearing, there is always a 10 direct relation between the table and the wheel andirregularities in the'wheel or work are apt to coincide periodically to produce imperfect work, whereas if there is no direct relation between the work and the grinding wheel, which is the-case when the work is reciprocated by liquid-pressure actuated means, there will be no periodic coincidence of irregularities and therefore a better and more even finish will be produced. In nan oral, liquid reciprocated grinding machines are cheaper to build than mechanically reciprocated grinding machines with their numerous necessary change gears. I

I- am aware that the work tables of grand- '25 ing machines have hitherto been reciprocated by liquid premre. These have usually been reciprocated by a unitary direction slow d ump with .the changesrin flow prouced y "an elaborate valve system. I believe that I am the first to employ a high speed, variable stroke, reversible flow pump for this purpose. By employing a pump of this type to reciprocate the work table of a inding machine, I produce the following vantages: The table is reciprocated at a much ,higher speed than hitherto, an infinite number of speeds of travel are possible and the reversible pump may be readily connected to a grindingmachine of this discription so addition of much separate mechanism. Due to the fact that this type of pump rotates at a very high speed, the table drive is much more even and thefinish is consequently smoother than in the slow-type of pump.

In addition to providing liquid operated means to reciprocate the work table, I preferably also provide liquid operated means to traverse the rotating tool holder across the work. By providing the combination oi as to be automatically reversed without theto provide liquid operating means for reliquid operated means fortraversing the tool and liquid operated means for reciprocating the work, as I do,,I permit the liquid operated means for traversing the tool to act as a shock absorber for the travel of the table at the end of each stroke. I also preferably so connect said liquid operated means for reciprocating the work table and liquid operated means for traversing the tool carriage that the traversing mechanism may act-between the strokes of the table reciprocating mechanism. In former types of machines, the traversin mechanism has itself been actuated direct y by the slowly moving table. In my machine, it is not necessary for the table to moveso far as in former devices or to use up suflicient energy to actually move the tool, it is merely necessary for the table to use up enough energy to trip the reversing I mechanism of the pump and then the liquid 7 operated traversing mechanism will operate of itself. The traversing mechanism operates very quickly and finishes its motion before the work table may begin to move back on the next stroke, thus savin the time which 75 would be wasted by the f ormer types of grinders in which a considerable motion of the slowly moving table was necessary to move the traversing mechanism. By permitting the liquid 0 rated means to actuate the traversing rotating tool and thereby to act as a cushioning device for the table or by providing pressure relief valves in the liquid system for traversing the table to function as cushioning devices as needed, I eliminate the necessity of employing an elaborate elastic, air cushioning system of cylinders, etc., for merly employed in machines of this type.

In addition, I believe that I am the first liquid from'the pressure liquid operated system. In former machines of this type, in order to secure the desired travel of the table, 1-10 .with my invention.

considerably reduced, thus saving a considerable amount of always valuable floor space and eliminating the hazard to workmen of dangerous extensions on the 1 moving table. By employing two pistons and their respective cylinders it is always powible to have the pistons pull the table in each direction instead of pushm it as formerly. By kee ing the piston ro in tension, it may be' m e much smaller than otherwise and trouble with leaka at the stufiing box atly reduced, and in ads of" ition the piston r may be kept in a line with the cylinders much more readily.

These and such other objects of my inven tion as may hereinafter appear will be best understood from a description of one embodiment thereof, such as is shown in 'the accompanying drawings. a

In the drawings, Fi re 1 is a-front elevation of a grinding mac ine equipped with my invention.

Figure 2 is ,a plan viewof said machine, with the column. and its attached parts removed.

Figure 3 is an end elevation of said machin 1 Figure 4 is a diagrammatic skeleton view, illustrating the functioning and coordination of the various elements of the liquid operated system constructed in accordance Figure 5 is an enlarged frontview of a part the tool carriage traversing mechanism.

along the line 66 of Figure 5.

Figure 7 is a sectional view taken along the line 7-7 of Figure 6.

In the drawings, wherein like characters of reference indicate like parts throughout, 10 generally indicates a grinding machine of the type having a reciprocatin work hold i table 12 and a carriage or a rotating grinding tool 14 normally traversed across the work. As explained, it is to the specific mechanism for traversing the rotating tool and for reciprocating the work holdingtable that my invention relates. The work hold ing table 12'is suitably mounted in runways 16 on the bed'18 of said machine, as usual.

The grinding machine 10 is provided with the usual carria 20 for mounting the grinding wheel spind e 22 thereon in the usual manner, which has the grinding wheel 14 mounted as usual on the front end thereof, so that the grinding wheel 14 may readily'rotate as usual above the work table 12. The grinding wheel spindle 22 is suitabl rotated as usual by the belt 24 driven in t e usual manner by the motor 26.

The wheel spindle 22- m... be

raised and lowered by the usuiil mechanisms on revolutions of the hand wheel 28. The vertical supporting carriage 20 for mounting the grinding wheel spindle 22 is mounted on the runway on the bed 18 so that the grind- 1n tahle in a manner to. be later explained. To

machine is also preferabl provide with a water supply line 32 which pours water onto the working tool 14, the water therefor being suitably supplied as usual by the water pump 34 actuated in any suitable manner by the motor 26. e

As stated, I provide liquid actuated means to reciprocate the work table 12, and also preferabl liquid actuated means'to traverse the grindin wheel 14 across the work. A source of liqui under pressure is necessary to actuate said means. As sucha suitablesource of liquid pressure, I provide a pump 40, having means to reverse the flow therefrom. In my preferred embodiment I preferably employ avariable speed reversible flow pum dnven at constant speed by a power-train romthe motor 26, preferably one ofthe Hele-Shaw type, such as is shown and described in Pat.

wheel 14 may be traversed across the work I rate of umping ma be varied, such as the 6 hand w eel 42, an means to reverse the flow therefrom which in the embodiment shown comprises the rod 44 It is obvious, however, that in place of a reversible flow pump, a unidirectional pump rovided with a valve system to reverse the ow therefrom Figure 6 1s a sectional .vlew thereof taken may be employed, "orthat the unidirectional pump be provided with a reversible drive therefor.

roe

As stated, I provide liquid actuated means on the machine bed 18 by means of the brackets 54, with their outer or stuflin'g box ends 56 preferably adjacent to each other and with-their opposite inner ends 58 referably pointing in opposite directions, said 150* and 50" -thus overlapping and extending in opposite directions on the machine bed 18.

I provide the pipe lines 60 and 60" to connect the pump 40 with each respective cylin-- 'der 50" and 50 preferably at the stufling box end 56 thereof, though they may be connected to said cylinders in any other suitable fashion. To reciprocate in said cylinders 5,0and 50",

preferably cylinders preferably no I ' et 55 at the other end of the table.

I provide the two piston rods 51and 51", each having the outer end 53 thereof attached to the base of the work holding table 12 by means of the bracket 55 and the opposite inner end thereof terminating in the piston head 57,-being thus adapted to be alternately, with changes in reversal of flow from'said pump, forced inwardly of said cylinders and 50" to thereby efi'e'ct a pulling movement of said work holding table 12.

The piston rod 51" passes through a boss on the bracket connected to the work holding table 12, the end of the rod 51 bein threaded and carryinga nut. Similarly t e rod 51 passes through a boss connected to the brack- The end of the rod 51" is also threaded and carries a nut. Said nuts are adapted to engagethe end of each boss, the rods being slidable in the respective bosses, thus forming a slidably engaging connection so that the table may be moved from one end of its stroke to the other by means of the rods, and in the movement of the table, the rods are thus subjected only to tension. It will be apparent that in the movement of the table to the right in Fig. 2 by means of the rod 51", the rod 51 is not su ected to compression, but in fact is subjected slightly to tension for the reason that the piston and the rod attached thereto are pulled to .the right by means of its respective nutand associated parts. Similarly in the movement of the work table to the left, which is accomplished by means of the piston head 57, the piston rod 51-and associated parts above described, the piston rod 51". is not subjected to compression but in fact is also subjected to slight tension in that the rod and associated parts are ulled to the left.

I also provide means to e ect a reversal of liquid flow to the space in each cylinder 50 and 50" between the outer ends 56 of said cylinders and the piston heads 57 to thereby cause a change of direction and the reciprocation of said table 12. In my-preferred em bodiment, said means includes a shaft (0 pivoted transversely of the machine, having the pinion 72 mounted thereon and the shipper rod 74 keyed thereto so as to extend upwardly therefrom. Ialso provide a horizontally movable rack 76 having the teeth 78 on one edge thereof adapted to be enmeshed by the teeth of the pinion 72. Said reciprocating rack 76 is suitablyvmounted in the guides 80 on the machine bed 18, and is provided at the opposite end thereofwith the cam 82. A lever 84 having the studs 86 and 86 projecting therefrom at a spaced distance is suitably p voted on a-bracket 88 attached to the machine bed 18. The opposite end of said lever 84 from the projecting stud 86,

terminatesin the arm 90, having the elongated link 02 pivotally attached thereto. The opposite end of said elongated 1111k 92 1s pivotally attached to the arm 94 of the bell crank lever 96 suitably pivoted on the bracket I 44 will act upon the pum "40 to cause a change in the direction of flow therefrom. The springs 104 having fixed bases anchored to the rod 44 are preferably provided to abut the slidable washers 102 to absorb the shock of suddenly reversing therod 44 at the end of each stroke so that it is not transmitted to the ump 40. It is obvious that said just descri ed means includes the pivoted member or shipper rod 74.

I provide means functioning automatically at the end of each table stroke to move said pivoted member or shipper rod 74 to actuate said flow reversing means. The preferred embodiment of such means includes the studs 106 and 106 mounted on the work table 12 so as to be longitudinally adjustable thereon.

The operation of said liquid operated table reciprocating means is obvious from the above description. When, as shown in Figure 4, the stud 106" strikes the shipper rod 74 as the table has almost reached the end of its, travel in the direction of the arrow, it will push the shipper rod 7 4 to the left, which will cause the rack 76 to move also toward the left, thereby causing the cam 8 to depress the lug 86 thereby raising the. Ii 92 which in turn will cause the end 100 to move outwardly to cause the rod 44 to move' outwardly to effect a reversal of the pump. As the table nears the end of its stroke in the opposite direction, it is obvious that the lug 106 will cause a reversal of these motions to obtain a flow of liquid in the opposite direction. i

In addition, I preferably provide manu ally operable means for independently actu -ating the flow reversible means to independently interrupt and reverse the table recip- In my preferred embodirocating means. ment, said means comprises the handle 110 secured to the shaft 70. It is thus obvious that the handle 110 will pivot the shaft 70 to reverse the flow from said pump to inde pendently interrupt or reverse the travel of the table 12 at the will of the operator.

I also preferably provide means to traverse firmly secured to the base of the grinding tool earl-1a 20. The rear end of the rod 122 is provided with a gear 126. I also pro vide the rod 128 extending transversely across the bed of the machine and suitably mounted on said bed 18, said rod 128 having the gear 127 at the rear end thereof adapted to drive through the medium of the idler gear 129, the

, y the runway gear 126 fast on the screw threaded rod 122. It is thus obvious that as the rod 128 is revolved, the transversely extending threaded I key the hub 130 to the front end of said tion which it is ke ed by medium of the handle 148 lng one end 141 thereof hub 130 pressed radially outwardly by t e P -136 of the pawl 120, thereltily thereto. in either dlrection.

1 ably shaft 128 by means of the key 131. Said hub 130 is provided with a segmental recess 132. The pawl is suitably pivoted on the hub within the recess 132. pawl 120 is provided with the projections 134 and 134" at each end thereof and has a V shaped projficl-tion 136 at the inner radial side thereof. e broken away portion 132 of the hub 130 is provided with a flat s ring blade 138, havfirmly secured to said the screw 140 and having its 0 posite en ring 142 against the V shaped projection holding the pawl in operative position in ei er direction. The blade 138 is provided with a central axial notch 144 adapted to receive the V sha progection 136 of said pawl 120 therein w en sal y means of revolving the shaft 146 on fastened on t e opposite exposed end thereof.

I provide the toothed sleeve 150 to revolve upon said hub 130. Said sleeve 150 is provided with the interior radially exposed axial notches 152 and the gear teeth 154 on the outer periphery thereof. It is obvious that as the pawl 120 is set first on one side and then on the other by'meansof the handle 148 that the respective projection 134 or 134" of said pawl 120- will engage in said notches 152 to permit the toothed sleeve 150to drive the ab 130 and co uently the shaft 128 keyed In addition to liquid o rated ineansto effect the reciprocation o the table, I preferably also provide li uid operated means automatically actuate by said pump on a change in liquid flow to actuatesaid traversing means, though it is obvious that mechamcal or other means may be provided for actuating the traversing mechanism if desired. I provide the bell crank lever suitivoted to the machine bed 18, as at 161, t e 'workarm thereof projecting upwardly therefrom and terminating in the toothed segment 162, -said toothed segment being adapted to engage the teeth 154 on the outer periphery of the sleeve 150. The power ipawl 120 is revolved to a neutral posi-V arm 164 of bell crank lever 160 ispreferably'provided with the longitudinal slot' 166. The stud shaft 168 is also mounted transversely on the machine bed 18. The front end of said stud 168 has a sleeve 170 loosely mounted thereon, the front end thereof terminating in the disc 172, having then groove 174 extending diametrically across the frontface thereof. The crank in 176 fastened in said groove 174 engages t e elongated slot 166 of the bell crank lever 160 whereby the se ent 162 is reciprocated upon a revolutiono said disc 172. The inner end of the sleeve 170 is ion 178.

A rack 180 is provided with the teeth 182 on one edge thereof ada ted to enmesh with the teeth of the pinion 1 8 to causearevolution of said sleeve 17 0. The-rack 180 is preferably provided with pistonheads 184 and 184" at each end thereof, though it is obvious provided with the pinthat a rack mechanism provided with two racks each having a piston head may be provided if desired. Cylinders 186 and 186" of slightly larger diameter than the diameter of the piston heads-184 and 184 are preferably provided to receive said respective piston eads. -The ipe lines 188 and 188" having the check via. ves 190 and 190 and 192 and 192 therein are provided to connect each cylinder 186 and 186 with the respective pipe lines 60 and 60", connecting said pump 40 indirectly through the transverse cylinders 186 and 186" to said table reciprocating cylinders 50 and 50", said pipe lines 188"; g

and 188"'with their respective valves bein so connected tothe said ipe lines 60 and 60 that the traversing mechanism may function on changes in direction of liquid flow prior to the reciprocation of the table and may provide a cushionin efi'ect for said table 12. In my improved em iment, I preferabl break saldlines 60 and 60" connecting 'sai pump 40 and said table reciprocating cylinders 50 and 50" and connect the pipe ines 188 and 188" and said traversing cylinders 186 and .186". to the respective broken ends thereof.

In my improved embodiment, the pipes. 60"

and 6O"v are broken into two arts 1943194",

196 and 196 respectively operating cylinders 186 and 186? and the y the traverse pipe lines 188 and'188". As thus broken,

as shown in my preferred embodiment, the

pipe line 60 includes the pipe line194 which" connects the traversing, liquid operating cylinder 186 with the table reciprocating cylinder ,50" and the pipe line 196, which con-" nects the pipelines 188 connected to the table traversing cylinder 186 with the pump 40.

The line 60 is'similarly broken up into the corresponding parts 194" and 196"; the line cylinder 186" with the tablereciprocating c linder 50 and the line 196 which connects 194" which connects the table traversing ersing cylinder 186 with the pump 40. The lines 194 and 194 enter the cylinders 186 and 186 at ports 195 and 195 near the center thereof. Check valve 192 and lines 188 permit the flow of liquid back from the cylinder 50 through lines 194 and 188 and through 196 into the pump; and similarly with the other side of the system. The check valve 190 is connected in the lines 196 and 188' to permit liquid to flow from the pump 40 into the cylinder 186 when it is at its extreme innermost position as shown in Figure 4 to force the piston head 184 outwardly to uncover port 198 whereby the liquid will be fed from the pump 40 into the cylinder 186 through the port 198, as well as 190.

to force the piston 184 outwardly, thereby line 194", the check valve 192 and the lines When the table 12 nears the end of its stroke,'the motion of the liquid from the pump will be reversed, and the liquid will then flow through the pipe 196, through the check valve 190 and force the traverse operatin rack' 180 and piston head 1'84 outwardly until the piston head 184 uncovers the port 195 near the middle of the cylinder and permits the liquid to flow t rough'pipe 194 to the cylinder This sudden increase of pressure in the cylinder 50 will stop the table 12, and the impact of stopping the table in its motion and re-starting it in the opposite direction will continue absorbing the shock of table reversal, the fluid in the end of the cylinder 186 adjacent the check valve 190 leaking outwards around the piston head 184 within the cylinder. This rapid motion of the rack 180 will be absorbed by the piston head 184 squeezing the liquid out through the port 198, so that the table 12 stops without shock. As the .line 194 is disconnected from the line 196 by the covering of port 195 by-the piston forced out from cylinder 50 and back into the pump 40. The check valve 192 is provided to permit this return flow from the cylinder 50 to the pump 40 to take place through 188" and 196", The function and method of operation of this valve system is thus shown; It is apparent that the traversing means functions at the end of each stroke of the work table 12 and before the beginning of its stroke in the opposite direction, and also acts as a cushioning device for said table.

In additionto the means just described for automatically actuating the traversing mechanism, I provide manually operable means to actuate said traversing mechanism. In my preferred embodiment said manually operable means comprises a hand wheel 200 on the I is moved to a neutral position; by means of the handle 148 so that the -shaped projection 136 thereof may register in the groove 144 of the spring blade 138.

To insure a supply of liquid in the liquid system at all times I preferably also provide turning the shaft 146throu h the medium of i pipes 206 and 206 leading from said reservoir 204 to said pump 40, said pipes 206 and 206 preferably terminating in one common pipe 206 discharging from the base of the reservoir 204. At convenient points in said pipes 206 and 206, I provide the check valves 208 and 208". It is thus obvious that when there is insuflicient liquid in the cylinders or the pipe lines, due to leakage or otherwise, the suction caused by the vacuum created thereby will open either check valve 208 or 208 to permit the deficiency to be made up from the supply of liquid 205 in the reservoir 204. This will serve to keep the suction side of the pump 40 at substantially atmospheric pressure. at all times.

In case any excessive" pressure is created in any part of the liquid system, whether it be a cylinder, pump,.etc., I provide the pressure relief valves 210 and 210 to eliminate the shock or hammer that would otherwise be caused thereby. Said pressure relief valves 210 and-210", preferably dischargeover the reservoir 204. I provide pipe lines 212 and 212 leading fromsaid valves to each table reciprocating cylinder 50 and 50 respectively in my; preferred embodiment through the traverse cylinders 186,? and 186. In my preferred embodiment I preferably only extend said pipe lines 212 and 121 to connect with the pipelines 206 and 206 leading from the reservoir to the pump. As said pressure relief valves 210 and 210 function also as cushioning devices, where the liquid operated means to actuate the traversing mechanism is employed as in my preferred embodiment they are not really necessary and maybe dispensed with, but they are absolute- 1y essentialv as cushioning means when the liquid operatedtable reciprocating means is i employed alone and function atthe end of each stroke.

In addition I provide ma'nually, controlled 1 I means to keep the table 12 from creeping when the work table is not being reeiprocated. In my preferred embodiment I preferably accomplish this by connecting a pipeline 214 across the pump 40, thus in my preferred embodiment the pipe line 214 13 connected to the pipe lines 60 and 60 leading from the table reciprocating cylinder 50 and.50 to the pump. I provide said pipe line 214 with the bypass valve 216 operable by the hand wheel 218 to equalize the pressure in said pipe lines 60 and 60 and thus across the pump to achieve a positive stop of said liquid operating mechanism when desired.

I also preferably provide the drain pipe lines 59 and 59 leading from the inner ends 58 of the cylinders 50 and 50 to the reservoir 204, to carry off any leakage past the pistons 57. I also preferably provide the drain pipe line 220 leading from the pump 40 to the reservoir 204 to carry away from the pump 40 the leakage inherent in that type of ump.

hough the means for manually controlling the table reciprocating means, the means for manually controlling the tool carriage traversing means and the means to prevent the table from creeping are valuable adjuncts of my machine, they may be omitted if desired.

Though I haveshown in my preferred em bodiment the work carriage reciprocated and the tool carriage traversed, it is obvious that the tool carriage may be reciprocated and the work carriage traversed without departing from the spirit of my invention, and that so long as one of these carriages ismoved by the liquid pressure means described, if desired the tool carriage may be reciprocated or the work carriage traversed in any other manner than by the liquid pressure system shown without departing from the spirit of my invention. I

As hitherto explained the liquid operated means for traversing the carriage for the rotating tool may be replaced by a mechanical or other device for this purpose, when as explained, the pressure reliefvalves become essential for cushioning the table.

\Vhereas I have shown in my preferred embodiment my invention employed with a surface grinding machine where the tool is actually moved across the work, it is obvious that it may be employed with a face grinding machine where the tool is merely, fed against the work as it is ground down, and I therefore in the claims employ the word traverse to signify any movement of one carriage substantially at right angles to the movement of the other reciprocating carriage.

It is understood that my invention is not limited to the specific embodiment shown and that various deviations may be made therefrom without departing from the spirit and scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a grinding machine, the combination of a work carriage, a carriage for a rotating tool, a pump havin means to reverse the flow therefrom, liquid actuated means actuated by reversal of liquid flow from said pump to effect a reciprocating movement of one of said carriages relative to said other carriage to bring the work on positively disposed piston heads,

one carriage in operative relation with the tool on the other carriage, including two pistons, two cylinders and pipe lines connecting said cylinders to said pump, whereby the volume of liquid in said system may be kept constant each piston being connected to said reciprocating carriage by piston rods always in tension to pull it alternately in opposite directions, liquid actuated means actuated by a reversal of flow from said pump to effect a movement of the other of said carriages transversely of said reciprocating carriage, and means actuated by the reciprocating carriage at the end ofeach stroke to automaticaly reverse the direction of liquid flow from said pump to change the direction of travel of said reciprocating carriage.

2. In a grinding machine, the combination of a work carriage, acarriage for a rotating tool, a reversible flow pump, liquid actuated means actuated by reversal of liquid flow from said pump to effect a reciprocating movement of said work carriage to bring the tool on the tool carriage in operative relation to the work on said work carriage, including two pistons, two c linders and pipe lines connecting said cylinders to said pump, whereby the volume of liquid in said system may be kept constant, liquid operated. means automatically actuatedby said pump to effect a movement of said tool carriage transversely of said reciprocating carriage, including rack mechanism having two opa cylinder of equal size for each piston head having a slightly larger internal diameter than the diameter of the piston head, and pipe lines provided with check "alves connecting each cylinder with the respective pipe lines connecting said pump and work carriage reciprocating cylinders so that the traversing mechanism may function on change in direction of liquid flow prior to the reciprocation of the work carriage and may provide a cushioning effect for said work carriage, and means actuated by the reciprocating carriage at the end of each stroke to automatically reverse the direction of liquid flow from said pump to change the direction of travel of said reciprocating carriage.

3. In a grinding machine, the combination of a work carriage, a carriage for a rotating tool, a pump having means to reverse the flow therefrom, liquid actuated means actuated by reversal of liquid flow from said pump to effect a reciprocating movement of one of said carriages relative to said other carriage to bring the work on one carriage in. operative relation with the tool on the other carriage, including two pistons. two cylinders and pipe lines connecting said cyl- III III

inders to said pump, whereby the volume of liquid in said system may be kept constant each piston being connected to said reciproeating carriage to pull it alternately in 0pposite directions by means of rods attached thereto through a connection operated to engage in only one direction so that the said rods are subjected to tension only, and means actuated by the reciprocating carriage at the end of each stroke to automatically reverse the direction of liquid flow from said pump to change the direction of travel of said reciprocating carriage.

4. In a grinding machine, the combination of a work holding table, a carriage for a rotating grinding tool, a pump having means to reverse the flow therefrom, liquid operated means actuated by said pump to reciprocate said table comprising two cylinders attached to the machine bed, a pipe line connecting each cylinder with said pump, two pistons attached to the base of said table reciprocated in said cylinders by liquid from said pump, means to effect a reversal of fluid flow to each cylinder, means functioning automatically at the end of each table stroke to actuate said flow reversal means, manually operable means for independently actuating said flow reversal means to independently interrupt and reverse the travel of said table, means to traverse the tool carriage, liquid operated means automatically actuated 'by said pump on a reversal of liquid flow to actuate said traversing means connected to the pipe lines connecting said pump and each table reciprocating cylinder in series so as to function prior to any reciprocation of said table, manually operable means to actuate said traversing means, a liquid reservoir, pipe lines connecting said pump to said reservoir,

check valves in said lines to insure a supply of liquid in said system, pressure relief valves discharging 'into said reservoir, pipe lines leading from each table reciprocating cylinder to said valves, and a pipe line connecting the pipe lines from said pump having a bypass valve'therein to equalize the pressure in said lines to achieve a positive stop of said liquidoperating mechanisms.

5. In a grinding machine, the combination of a workholding table, a carriage for a rotating grinding tool, a pump having means to reverse the flow therefrom,'liquid operated means actuated by said pump to reciprocate said table comprising two cylinders attached to the machine bed, a pipe line connectingeach cylinder with said ump, two pistons attached to the base of said table reci rocated in said cylinders by liquid from said pump, means to efl'ect a reversal of liquid flow to each cylinder, means functionin automatically at the end of each table stro e to actuate said flow reversal means, means to traverse the-tool carriage, liquid operated means automatically actuated by said pump on .a reversal of'liquidflow to actuate said traversing meansconnected to the ipe lines connecting said pump and each ta le reciprocating cylinder in series so as to function prior to any reciprocation of said table.

6. In agrinding machine, the combination of a work holding table, a carriage for a rotating grinding tool, a pump having means to reverse the 'flow therefrom, liquid operated to actuate said flow reversal means, manually operable means for independentl actuating said flow reversal means to in ependently interrupt and reverse the travel of said table, a liquid reservoir, pipe lines connecting said pump to said reservoir, check valves in said pump to said reservoir, check valves in said lines to insure a supply of liquid in said system, pressure relief valves discharging into said reservoir pipe lines leading from each table reciprocating cylinder to said valves, and a pipe line connecting the pipe lines from said pump having a bypass valve therein to equalize the pressure in said lines to achieve a positive stop of said liquid operated mech-' anisms.

7. In a grinding machine, the combination of a Work holding table, a carriage for a rotating grinding tool, a pump having means to reverse the flow therefrom, liquid operated means actuated by said pump to reciprocate said table comprising two cylinders attached to the machine bed, a pipe line connecting each cylinder with said pump, two pistons attached by means bf a slidably engaging connection to the base of said table alternately forced inwardly of said cylinders to sub ject said rods to tension only and to eflect a pullingmovement of the table by liquid from said pump, means to effect a reversal of liquid flow to each cylinder, and means functioning automatically at the end of each table stroke to actuate said flow reversal means.

8. In a grinding machine, the combination of a work holding table, a carriage for a rotating grinding tool, a pump havin means to reverse the flow therefrom, liqui operated means actuated by said pump to reciprocate said table comprising two cylinders attached to the machine bed, a pipe line connecting each cylinder with said pump, two pistons at: tached to the base of said table alternately forced inwardly of said cylinders to effect a pulling movement of the table by liquid from said pump, means toefi'ect a reversal of liquid to actuate said flow reversal means, means to traverse the tool carria e, and liquld operated means automatica y actuated by said pump on a reversal of liquid flowv to actuate said traversi means. r

9. In a grin ing machine, the combination of a work holding table, a carriage for a rotating grinding tool, a ump having means to reverse the flow there om, liquid operated means actuated by said pum to reciprocate said table comprising two cy inders of equal size having stufling boxes at one end thereof attached to the machine bed parallel to each other with their stufling box ends adjacent and overlapping and their other ends pointing in opposite directions, a ipe line connecting the stufling box end 0 each cylinder with said pump, two iston rods each having one end thereof attac ed to the base of said table and the opposite end thereof terminating in' a piston pump forced inwardly of said cylinders to thereby effect a pulling movement of said table, means including a pivoted member to efiect a reversal of liquid flow to each cylinder, means functioningautomatically at thepivoted member for independently actuating said flow reversal means to independently interrupt and reverse the travel of said table,-

means to traverse the tool carriage including a manually reversible pawl to change the direction of traverse, liquid operated means. au-

, tomatically actuated by said pump on a change in liquid flow to actuate said traversing means, including rack mechanism having two oppositel disposed piston heads, a cylinder of equa size for each piston head having a slightly larger internal diameter than the diameter of its re ective piston head, and pipe lines provid 7 connecting each cylinder with the respective pipe lines connecting said pump and table reciprocating cylinders so that the traversing v mechanism 'mayfunction on change in directionof li uid flow prior to the reciprocation of the ta 1e and may provide a cushioning effect for said table, manually operable means to actuate said] traversing means, a liquid.

e reservoir, ipe lines leading from said resertoinsureasup voir'to sai pump, 3

pressure relie valves discharging into sai reservoir, pipe lines leading from each table reciprocating cylinder tosaid. valves, and a pipe line connecting the pipe lines from said pum having a by-pass valve therein to equalpressure in said line'site. achieve astop of said liquid operated mech- I we t e positive 10'. In a grindm ead adapted to be alternately withchanges in reversal of flow from saidwith check valves to reverse the flow there check valves in said lines 7 of liquid in said I j whine, the conibilia; #6 tion of a work 'holging table, a carriage for rods each having one end thereof attached to the base of said table and the opposite end thereof terminating in a piston head adapted ,to be alternately,'with changes in reversal of flow from said pump, forced inwardly of said cylinders to thereby efiect a pulling movement of said table, means including a pivoted member to effect a reversal of liquid flow to each cylinder, means functioning automatically at the end of each table stroke to move said pivoted member to actuate said flow reng boxes at versal means, means to traverse the tool car- I riage including a. manually reversible pawl to change the direction of traverse, liquid operated means automatically actuated by. said pump on a change in liquid flow to actuate said traversing means, including rack mechanism having two oppositely disposed piston heads, a cylinder of equal size for each piston head having a slightly larger internal diam.- eter than the diameter of its respective piston ,head, and pipe lines provided with check valves connecting each'cylinder with the respective pipe lines connecting said pump and table reciprocating cylinders so that the traversing mechanism may function on change in direction of liquid flow prior to the v reciprocation ofth table and may provide a cushioning efiect for said table.

11. In a rinding machine, the combination of'a work olding table', a carriage for a rotating grinding tool, a fpump having means rom, liquid operated means actuated by said pump to reciprocate said table comprising two cylinders of equal size having stufling boxes at one end thereof attached'to the machine bed parallel to each other with their stufling' box ends adjacent and overlapping and their other ends pointing in opposite directions, a ipe line con-v necting the stufling box end 0 each cylinder with said pump, two iston rods each ha one end thereof attac ed to the base of table through a connection operating to ensaid base sothat the rod is subjected.

opposite end thereof ead adapted to be with c ange's in reversal of flow I pump formed inwardly of-said, cylinders to thereby eflect a pulling moveto tension andthe terminating in a iston alternate] from saicl ment of said table, means including a pivoted; member toefi'ect a reversal of liquid flow to I each cylinder, means functioning automati-.

cally at the end, of each table strokev to move I said pivoted member to actuate said flow reversal means, and manually operable means attached to said pivoted member for independently actuating said flow reversal means to independently interrupt and reverse the travel of said table, a liquid reservoir, pipe lines leading from said reservoir to said pum check valves in said lines to insure a supp y of liquid in said system, pressure relief valves discharging into said reservoir, pipe lines leading from each table reciproeating cylinder to said valves, and a pipe line connecting the pipe lines from said pump having a bypass valve therein to equalize the pressure in said lines to achieve a ositive stop of said liquid operated mechanlsms.

12. In a grindin machine, the combination of a work holding table, a carriage for a rotating grinding tool, a pump having.

means to reverse the flow therefrom, liquid operated means actuated by said pump to reciprocate said table comprising two cylinders of equal size having stufling boxes at one end thereof attached tothe machine bed parallel to each other with their stufling box ends adjacent and overlapping and their other ends pointing in opposite directions, a pipe line connecting the stuffing box end of each cylinder with said pump, two piston rods each having one end thereof and attached to the base of said table by means of a connection operating to engage said base in only one direction so that each rod is subjected only to tension and the opposite end thereof terminating in a piston head adapted to be alternately with changes in reversal of flow from said pump forced inwardly of said cylinders to thereby effect a pulling movement of said table, means including a pivoted member to effect a reversal of liquid flow to each cylinder, and means functioning automatically at the end of each table stroke to move said pivoted member to actuate said flow reversal means.

13. In a grinding machine, the combina tion of a work carriage, a carriage for rotating tool, a pump having means to reverse the flow therefrom, liquid actuated means actuated by reversal of liquid flow from said pump to effect a reciprocating movement of one of said carriages relative to said other carriage to bring the work on one carriage in operative relation with the tool of the other carria e, including two operable piston faces, cy 'nder means and pipe lines connectin said cylinder means to said pump, where y the volume of liquid in said system may be kept constant, each piston face being connected to said reciprocating carriage by means of a rod through a form of connection permitting tension only in said rod by means of a rod through a form of connection permitting tension only in said rod to pull it alternatel in opposite directions, and means actuate by the reciprocating carriage at the end of each stroke to automatically reverse the direction of liquid flow from said pump to change the direction of travel of said reciprocating carriage.

14. In a inding machine the combination of a work-holding table, a carriage for holding a rotating grinding tool, a pump having means to reverse the flow therefrom, fluidoperated cylinder means having piston means therein actuated by said pump to reciprocate said table, pipe-line means connecting the cylinder means with said pump, said piston means in said cylinder means being so arrangedthatthe operable iston faces are acted upon by fluid from sai pump, a piston rod to actuate said table so-cqpfiected to each of said faces and to said work-holding table that the fluid forces act to produce tension only in the piston rods, means to effect a reversal of fluid flow to said cylinder means, and means automatically functioning at the end of each table stroke to actuate said flow reversal means.

15. In a grindin machine the combination of a work-hol ing table, a carriage for holding a rotating grinding tool, a pump having means to reverse the flow therefrom,

fluid operated cylinder means comprising a v plurality of cylinders having piston means therein actuated by said pump to reciprocate said table, pipe-lme means connecting the cylinder means with said pump, said piston means being so arranged that the operable piston faces are acted upon by fluid from said pump, piston rods to actuate said table so connected to each of the pistons and to the work-holding table that the fluid forces act to produce tension only in the piston rods, means to effect a reversal of fluid flow to said cylinder means, and means automatically functioning at the end of each table stroke to actuate said flow reversal means.

FRANK E. STRATTON. 

